Devoxx 2011 - Scaffolding with Telosys

A pragmatic scaffolding approach

to build Java Web Applications

Laurent Guérin

Telosys Project Leader

Sogeti & OW2 Consortium

Devoxx 2011 – Laurent Guérin – JAVA scaffolding with Telosys ( http://www.telosys.org )

Introduction

Laurent Guérin : Person

[email protected]

Sogeti : Company Capgemini : Company

OW2 : Consortium

Telosys : Project

belongs to

leads

hosts

: Plateform

: IDE

: License

2

France : Country

located in


Introduction

OUTLINE :

- Code generation

- Telosys approach

- The framework

- The tools (demo)

3

About code generation …


Model Driven

• "Model-First" approach ( MDD, MDA, … )

• Code generation from an existing model

• "Model Driven" => You need a model !

• Model => substantial initial investment

• Process : keep the model up to date !

Code

MODEL

Part

name

Message

name

0..n+part 0..n

Service

name

Port

name

0..n+port 0..n

Port Type

nameBinding

name1

+binding

1

1

+type

1

Param

name

1+message 1

Output

Input

StartWithExtensions

BindingFaultFault

name1

+message

11

BindingOperation

name

0..n+operation 0..n0..1 +input0..1

0..1+output 0..1

0..n

Operation

name0..1

+input

0..1

0..1

+output

0..1

0..n+fault 0..n

0..n+operation 0..n

11

1

+fault 0..n

X M I( XML )

TemplateTOOL

5

Split !


Scaffolding

• "Database-first" approach

• Very efficient

• No customization between the database

metadata and the generator

• Not enough information …

– Java field name

– Java field type

– Validation rules : min, max, regexp, …

– Boolean storage values ( 1/0, "T"/"F", … )

– etc …

• Cannot store/reuse further information

Database

TOOL

Code

Metadata

Template

6


Wizards

• Code generation without model / DB

• IDE tool => Needs user inputs

• Can also use existing artefacts

as input

– Java class Java class

– WSDL file Java classes

• Efficient only for a few kinds of

targets

• Can only be considered as

"development accelerators"

Code

Workspacefiles

I.D.E.

“Java Model”org.eclipse.jdt.core

7

Bulkgeneration

The Telosys approach


Telosys approach

• What we want …

– to be able to generate code quickly for entities

management (like scaffolding) with a simple tool

– to add and keep specific information about entities

=> we need a repository to store them (kind of model)

• What we don’t want …

– to spend a lot of time to build a model

– to input further information for each generation

• What we must have …

– a database (“database first”)

– an IDE (Eclipse) that is the developer’s daily tool 9

+DB

Metadata


Telosys approach

• The 3 steps …

Database

Repository

generator

Metadata

Repository(Lightweight

model)

Code

Code

generator

Template

generates

updates

modify & add

information

Use the

“Database-first”

approach to build

a “lightweight model”

Customize the

“lightweight model”

Generate

the code

1 2 3

updates customizes

10


The tripod of success

• The framework is self-sufficient to build a

complete Web application

( "global" / "full stack" framework )

• The tools are provided as Eclipse plugins in

order to make the programmer's life easier

( agile )Method

Framework Tools

( code generation ) ( global & simple )

What a

development

project needs…

11


Project’s philosophy

• “Keep it simple and stupid”

( KISP ? )

– lightweight framework

– small tools (easy to install & to use)

• “Conform with the standards”

– servlet/JSP/JSPX, JDBC, JPA, http, XML, …

• “Remain open”

– Open Source (hosted by OW2 consortium)

– Open Format (lightweight model = XML)

– Customizable templates different targets :

Telosys fwk + other Java Frameworks, Flex, PHP, … 12

The Telosys framework


The framework

• Global framework “all in one“

• Only one jar (+ JDBC) => no "jar hell" !

• Designed for "data centric" web applications

• Light (just needs a servlet container and a

database) & based on simple concepts14


The "global effect"

• “Global” means … less “glue”, less objects (less memory footprint), less configuration, …

=> Coherence & Efficiency

• “Modular” (modules usable separately)

PersistencePresentation Application

ScreenMaps

Services

ScreenManagers

Business

DAO

Java Beans ( POJO )

XML conv

Authenti-cation

Commons, logging, I18N, …

AJAXJSP + taglib

FrameworkJavascript

SQL

Services

Natively AJAX

One framework that covers all the application layers

"VO"

Very simple objects( "Pure POJO" )

Thin persistence layer

15


The "client-server" paradigm

• Once the screen is loaded in the browser, it

converses with the server via AJAX requests

( XML / http )

Client-sideScreen

Manager

ServiceJavaS

cri

pt

Fra

mew

ork

Server-side<request screen-name="Employee"

screen-id="0" action="get" >

</request>

<response screen-name="Employee"

screen-id="0" action="get" >

<return code="0" message="Ok" >

</return>

<data>

<employee id="23" lastName="Wayne"

firstName="John" manager="0" email="" />

</data>

</response>

<response service-name="Add">

<return code="0" message="Ok" />

<values> <value result="8" /> </values>

<data> </data>

</response>

http://myhost:8080/.../Add.svc?p1=2&p2=6

Action

Serv

ice

http

16


DataSet

VO List

VO Bean

The "Data Objects"

• VO Bean (POJO = “entity record”)

• VO List (selectable/sortable list of POJO)

• DataSet (grid of objects)

DatabaseData

Access

LayerXML

Con-

verters

ParsersFiles

XML

< … >

</ … >

Book

.java

BookList

.java

BookConv

.java

BookDAO

.java

Book

Table

Code

generator

17


The "Data Access Layer"

• Why another persistence framework ?

ORM : JPA (or Hibernate) …High level & "Object Oriented"Hides the complexity Sometimes misunderstood by the developers ( "lazy/eager" loading, cache effects, "attached/detached" entities, "owning side"/"inverse side" links, … )

JDBC APILow level

Telosys DAL (based on DAO pattern)Intermediate level & "Record Oriented"One Bean = One RecordThe developer keeps the control No links, no cache, no byte-code enhancement Very simple API : load, save, insert, update, exists, loadList, updateList, …

Both are useful,

You have the choice …

18

Java objects

rule the persistence

DB

new new

DB

Database records

rule the persistence

new legacy


"Record Persistence" examples

EmployeeDAO dao = getDAO();

Employee employee = new Employee();

employee.setCode( "123" ); // primary key

int r = dao.load(employee, db);

if ( r > 0 ) { // if found

// update

employee.setFirstName("Bill");

dao.update(employee, db);

}

else {

// create

employee.setLastName("Wayne");

employee.setFirstName("John");

employee.setEmail("[email protected]");

dao.insert(employee, db);

}

if (dao.exists(employee,db)){...}

dao.delete(employee, db);

The developer decides…

. What to do

. How to do it

. When to do it

db.commit();

db.rollback();

A "record" = a bean (POJO)

Each bean is managed by a dedicated DAO

EmployeeList list = new EmployeeList();

ListQuery query = dao.createQuery(…);

int count = dao.count(query, db);

dao.loadList(query, list, db);

dao.updateList(list, db);

19


Links or no links ?

• You have the choice …

• Links can be generated if an “object graph

approach” is chosen (ie with JPA persistence)

• With a “record approach” : no need to manage

links between beans, the framework uses

“aggregations” to assemble required beans

Aggregation

(composite)

20

@ManyToOne

@OneToMany

@ManyToMany

@OneToOne

Code

generator

DAO

Code

generator

Bean

Bean


The screens

Book (bean)

ScreenData

(aggregation

0 .. N objects)

ScreenManager ScreenProcedure

AuthorList

Shop (bean)

ScreenMap

DataSet

BookProc

.java

BookMgr

.java

BookData

.java

Book.jsp

( or .jspx)

Book.js

M

V CAJAX

acts on …

request

response

Code

generator

21


Screen view example

JSP or JSPX, but no HTML !

22

<%@ taglib uri="/telosys/widgets" prefix="t" %>

<t:screenbody>

<t:label id="L_EmpId" x="40" y="60" txt="Employee Id : " cl="PK_field_label" />

<t:label id="L_LastName" x="40" y="100" txt="Last name : " />

<t:label id="L_FirstName" x="40" y="140" txt="First name : " />

<t:label id="L_Birthdate" x="40" y="180" txt="Birthdate : " />

<t:field x="200" y="60" id="EmpId" cl="PK_field" size="6" maxlength="6" />

<t:field x="200" y="100" id="LastName" size="30" maxlength="30" value="Aaaa" />

<t:button x="460" y="100" id="b1" txt="My button" onclick="b1_onClick();" />

<t:field x="200" y="140" id="FirstName" size="30" maxlength="30" value="Georges" />

<t:field x="200" y="180" id="Birthdate" size="10" maxlength="10" value="" type="Date" />

<t:radiogroup id="Contract" x="200" y="220">

<t:radioitem id="R_field61" x="0" y="0" value="1" txt="C.D.D. (1)" />

<t:radioitem id="R_field62" x="0" y="20" value="2" txt="C.D.I. (2)" />

</t:radiogroup >

<t:checkbox id="Manager" x="340" y="220" value="1" valueoff="9" txt="Manager" />

</t:screenbody >


Conventions

• "Framework" => "Frame" !

• "CoC" ( Conventions over Configuration )

– The developers know where the files are

– The tools know where to generate files

• Example : 1 Java package 1 web folder

1 screen = +

23


What is a Telosys project ?

• Just a standard Java Web Application project

• It can be organized for Maven, or not…

• In Eclipse :

1) Create a new "Web Dynamic project"

2) Import the "Telosys Starter Kit“24

That’s all !

The project is ready

for development and

code generation

src (server side)

TelosysTools (+)

WebContent (client side)

deployment

.war


Demo

• How to create a Telosys project …

1) Create a Dynamic

Web Project 2) Import the

Telosys starter kit

25


Demo (cont’d)

• Test and initialize the Telosys project …

3) Test the

project

( run it )

4) Define the

conventions

26

The Telosys Tools


The big picture

Template

.vm

Repository.dbrep

( XML )

Velocity

Context

Repository

generator

Code generator

28

WizardsEditors Properties

.jsp / .jspx

.js

.java

other …

Database

Meta-data

Everything can be

done in Eclipse


The demo

• Connection to the database

• Repository generation

• Repository customization

• Basic objects generation (Bean, List, DAO, Conv.)

• Screens generation (server side & client side)

• Template customization

• Links management

• Beans generation for JPA & Validators

• New specific template

29

See demo screenshots at

the end of this presentation

Conclusion


Conclusion

31

Database Repository Tools Initial code

and the project is

on the rails…


In the future …

• Main goals in the 2012 roadmap

– Repository

• Extendable/unlimited information for

each entity and each Java field

– Screens design

• Official release of the Screen Builder

plugin (WYSIWYG)

– Java Portals

• JSR-168 portlet to embed

screen maps in a portal page

– NoSQL

• DAO for GAE/BigTable & Cassandra

32

Still a lot

of work to

improve

the rails …

Questions ?

Appendix


Framework features

Services

Text/CSV files parser

File upload/download

Internationalization

DataSet

XML converters

SQL DAO

Selectable/Sortable

beans lists

AuthenticationLogging

Commons/util classes

Widgets TagLib

JavaScript framework

Screen Maps

35


Telosys Screen Builder

36

A visual tool to design the Telosys Screens

( beta version )


Follow the project …

• Web site : http://www.telosys.org

• LinkedINhttp://www.linkedin.com/groups?gid=1340197

• Twitter http://twitter.com/telosys

• Viadeo (in french)

http://www.viadeo.com/hu03/0024uydjnnwew6j/telosys

37

http://www.telosys.org/

http://www.linkedin.com/groups?gid=1340197

http://twitter.com/telosys

http://www.viadeo.com/hu03/0024uydjnnwew6j/telosys

The demo…


Repository

Generator

Demo

• Use the database meta-data to generate the

initial repository

Database

Repository.dbrep

( XML )

Generationrules

39


Demo (cont’d)

• The generated repository is editable

with an Eclipse plugin editor

O/R Mapping

Database Java Attributes

Java Classes

Database

updatable

40


Demo (cont’d)

• Java fields :

– Each Java field can have additional information

– Useful for

• JSP/TagLib user input validation

• "Bean Validation " annotations ( JSR 303 )

or "Hibernate Validators"

41


Demo (cont’d)

• Bulk generation

42


Demo (cont’d)

• Generator templates

– The generator is based on "Velocity"

– The templates ( ".vm" files ) can be modified in order

to conform with each project requirements

• coding style

• comments

• etc… i.e. :

add/remove

serialization

43


Demo (cont’d)

• Entities links

– The foreign keys can be used to generate

links between entities

–Useful for JPA beans generation

44


Demo (cont’d)

• Generator project’s variables

– Each project can

define its own

specific variables…

… and use them

in the templates

45

#if ( $bean_jpa == "1" )

$link.jpaAnnotations(4)

#end


Demo (cont’d)

• Adding a new specific template

– 1) create the new “.vm” file

– 2) add it in the “templates.cfg” file

–3) use it in the tool …

46

HTML documentation ; ${BEANNAME}.html ; doc/html ; vo_doc_html.vm

vo_doc_html.vm

Title File Folder Template


Demo (cont’d)

• Using wizards

47

New …

The end

Technology

Devoxx 2011 - Scaffolding with Telosys